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Archive for the ‘quantum physics’ category: Page 253

Dec 8, 2022

A room-temperature terahertz camera based on a CMOS and quantum dots

Posted by in categories: food, law enforcement, particle physics, quantum physics, security

Terahertz (THz) radiation is electromagnetic radiation ranging from frequencies of 0.1 THz to 10 THz, with wavelengths between 30μm and 3mm. Reliably detecting this radiation could have numerous valuable applications in security, product inspection, and quality control.

For instance, THz detectors could allow law enforcement agents to uncover potential weapons on humans or in luggage more reliably. It could also be used to monitor without damaging them or to assess the quality of food, cosmetics and other products.

Recent studies introduced several devices and solutions for detecting terahertz radiation. While a few of them achieved promising results, their performance in terms of sensitivity, speed, bandwidth and operating temperature is often limited. Researchers at Massachusetts Institute of Technology (MIT), University of Minnesota, and other institutes in the United States and South Korea recently developed a that can reliably detect THz radiation at room temperature, while also characterizing its so-called polarization states. This camera, introduced in a paper published in Nature Nanotechnology, is based on widely available complementary metal-oxide-semiconductors (CMOS), enhanced using (i.e., nm-sized semiconductor particles with advantageous optoelectronic properties).

Dec 8, 2022

Wormholes in a Lab? How About String Theory & Extra Dimensions Too?

Posted by in categories: cosmology, quantum physics

Did you hear that #physicists simulated a baby #wormhole in a lab? Well, it’s even more true that #StringTheory and #ExtraDimensions were discovered in the ’60s. Think I’m joking? I’m not. To learn what’s true/false in the wormhole story, read this first.

Dec 8, 2022

In a world first, physicists move light back and forth in time simultaneously

Posted by in categories: computing, quantum physics

The experiment could help to form a unified theory of quantum gravity.

Scientists have, for the first time ever, made light appear to move simultaneously forward and backward in time. The new method, achieved by an international group of scientists, could help create novel quantum computing techniques and give scientists a better understanding of quantum gravity, a report from LiveScience.

It was achieved thanks to a combination of two principles that form a part of the bizarre world of quantum mechanics.

Continue reading “In a world first, physicists move light back and forth in time simultaneously” »

Dec 8, 2022

Researchers plan to use quantum computers in search for dark matter

Posted by in categories: computing, cosmology, particle physics, quantum physics

This research could potentially lead to a better understanding of the galaxy and its many mysteries.

It’s a cosmic riddle: How can galaxies remain together when all the matter we observe isn’t enough to keep them intact? Scientists believe an invisible force must beat play, something so mysterious they named it “dark matter” because of its lack of visibility.

This mysterious presence accounts for nearly three times more than what we can observe — a startling 27% of all existence! The mysterious dark matter is a profound mystery to scientists, its existence making up nearly one-third of the universe’s energy and mass yet remaining elusive due to its ability to avoid detection.

Continue reading “Researchers plan to use quantum computers in search for dark matter” »

Dec 8, 2022

Why 21 cm is the magic length for the Universe

Posted by in categories: quantum physics, space

Photons come in every wavelength you can imagine. But one particular quantum transition makes light at precisely 21 cm, and it’s magical.

Dec 8, 2022

Timeless Explanation: A New Kind of Causality, Julian Barbour

Posted by in categories: information science, quantum physics

There are serious indications from attempts to create a quantum theory of gravity that time must disappear completely from the description of the quantum universe. This has been known since 1967, when DeWitt discovered the Wheeler-DeWitt equation. I shall argue that this forces us to conceive explanation and causality in an entirely new way. The present can no longer be understood as the consequence of the past. Instead, I shall suggest that one may have to distinguish possible presents on the basis of their intrinsic structure, not on the basis of an assumed temporal ordering. If correct, this could have far-reaching implications. Hitherto, because the present has always been interpreted as the lawful consequence of the past, science has made no attempt to answer ‘Why’ questions, only ‘How’ questions. But if there is no past in the traditional sense, we must consider things differently. Thus, if we eliminate time, we may even be able to start asking “Why” questions.

Specification of a point and tangent vector in conformal superspace (CS) determines a slab of spacetime in CMC foliation and unique curve in CS.
Almost perfect implementation of Mach’s principle because local inertial frames, local proper distance and local proper time all emergent and determined by the universe’s shape and shape velocity.
The Mystery: Shape velocity, as opposed to shape direction, is last vestige of Newton’s absolute space and time. Responsible for expansion of the universe and perhaps perfect transformation theory in quantum theory of the universe.

Continue reading “Timeless Explanation: A New Kind of Causality, Julian Barbour” »

Dec 8, 2022

‘Quantum time flip’ makes light move simultaneously forward and backward in time

Posted by in categories: computing, particle physics, quantum physics

After recombining the superposed photons by sending them through another crystal, the team measured the photon polarization across a number of repeated experiments. They found a quantum interference pattern, a pattern of light and dark stripes that could exist only if the photon had been split and was moving in both time directions.

“The superposition of processes we realized is more akin to an object spinning clockwise and counter-clockwise at the same time,” Strömberg said. The researchers created their time-flipped photon out of intellectual curiosity, but follow-up experiments showed that time flips can be paired with reversible logic gates to enable simultaneous computation in either direction, thus opening the way for quantum processors with greatly enhanced processing power.

Theoretical possibilities also sprout from the work. A future theory of quantum gravity, which would unite general relativity and quantum mechanics, should include particles of mixed time orientations like the one in this experiment, and could enable the researchers to peer into some of the universe’s most mysterious phenomena.

Dec 8, 2022

The process algebra model: A new way of constructing reality

Posted by in categories: biological, mathematics, particle physics, quantum physics

The concept of ‘anti-realism’ is widely seen as a fact of life for many physicists studying the mysterious effects of quantum mechanics. However, it also seems to contradict the assumptions of many other fields of research. In his research, Dr William Sulis at McMaster University in Canada explores the issue from a new perspective, by using a novel mathematical toolset named the ‘process algebra model’. In suggesting that reality itself is generated by interacting processes more fundamental than quantum particles, his theories could improve researchers’ understanding of fundamental processes in a wide variety of fields.

The concept of ‘locality’ states that objects and processes can only be influenced by other objects and processes in their immediate surroundings. It is a fundamental aspect of many fields of research and underpins all of the most complex systems we observe in nature, including living organisms. “Biologists and psychologists have known for centuries that the physical world is dominated by processes which are characterized by factors including transformation, interdependence, and information”, Dr Sulis explains. “Organisms are born, develop, continually exchange physical components and information with their environment, and eventually die.”

Beyond biology, the principle of locality also extends to Einstein’s theory of special relativity. Since the speed of light sets a fundamental speed limit on all processes in the universe, the theory states that no process can occur if it has not been triggered by another event in its past, at a close enough distance for light to travel between them within the time separating them. In general, these theories are unified by a concept which physicists call ‘realism’. Yet despite this seemingly intuitive rule, physicists have increasingly come to accept the idea that it doesn’t present a full description of how all processes unfold.

Dec 7, 2022

Researchers develop a scaled-up spintronic probabilistic computer

Posted by in categories: chemistry, information science, particle physics, quantum physics, robotics/AI

Researchers at Tohoku University, the University of Messina, and the University of California, Santa Barbara (UCSB) have developed a scaled-up version of a probabilistic computer (p-computer) with stochastic spintronic devices that is suitable for hard computational problems like combinatorial optimization and machine learning.

Moore’s law predicts that computers get faster every two years because of the evolution of semiconductor chips. While this is what has historically happened, the continued evolution is starting to lag. The revolutions in machine learning and means much higher computational ability is required. Quantum computing is one way of meeting these challenges, but significant hurdles to the practical realization of scalable quantum computers remain.

A p-computer harnesses naturally stochastic building blocks called probabilistic bits (p-bits). Unlike bits in traditional computers, p-bits oscillate between states. A p-computer can operate at room-temperature and acts as a domain-specific computer for a wide variety of applications in machine learning and artificial intelligence. Just like quantum computers try to solve inherently quantum problems in , p-computers attempt to tackle probabilistic algorithms, widely used for complicated computational problems in combinatorial optimization and sampling.

Dec 7, 2022

Quantum processor reveals bound states of photons hold strong even in the midst of chaos

Posted by in categories: quantum physics, robotics/AI

Researchers have used a quantum processor to make microwave photons uncharacteristically sticky. They coaxed them to clump together into bound states, then found that these photon clusters survived in a regime where they were expected to dissolve into their usual, solitary states. The discovery was first made on a quantum processor, marking the growing role that these platforms are playing in studying quantum dynamics.

Photons—quantum packets of electromagnetic radiation like light or microwaves—typically don’t interact with one another. Two crossed flashlight beams, for example, pass through one another undisturbed. But in an array of superconducting qubits, microwave photons can be made to interact.

In “Formation of robust of interacting photons,” published today in Nature, researchers at Google Quantum AI describe how they engineered this unusual situation. They studied a ring of 24 that could host . By applying quantum gates to pairs of neighboring qubits, photons could travel around by hopping between neighboring sites and interacting with nearby photons.